Question

Flag For Review If the units digit of the three-digit positive integer k is nonzero, what is the tens digit of k ? (1) The tens digit of k + 9 is 3. (2) The tens digit of k + 4 is 2.

Answer 1

Answer: Statement 1 alone is sufficient and Statement 2 is not.

Explanation:

Consider Statement 1:

Choose numbers to resolve it,

If unit digit of k takes from 1 to 9, then adding 9 would definitely increase the tens digit by 1, so it gives 2. And this is sufficient to answer the question.

Consider statement 2:

If unit digit takes any number between 1 to 5, then as you add, the 4 tens digit would remain the same.

So in this case it would be 2, but if unit digit take from 6 to 9, tens digit would increase by 1, in which case it becomes 1.

Therefore, Statement 1 alone is sufficient and Statement 2 is not.